The invention is described in relation to the processes by which catalytical gasoline and intermediate distillates of crude oil are produced, and more specifically, of sulfer-reduction in catalytical gasoline and intermediate distillates of crude oil.
Sulfur is found in deposits of crude oil and is one of its principal contaminants. This crude-oil contaminant produces severe corrosion problems at refining companies and is one of the principal contaminants in petroleum-derived fuels (gasoline, diesel fuel, turbine fuel, etc.). Today, there are a variety of processes by which the amount of sulfer in intermediate distillates of crude oil (turbine, gasoline, and Diesel fuel) can be reduced in the world""s oil refineries. The most commonly used of these processes are Hydrodesulfurization plants and Perco plants whose process employs aluminum-charged catalytic chambers operating at temperatures from 380xc2x0 C. to 430xc2x0 C.
Both processes require installation of a plant with various types of costly, sophisticated equipment (heat exchangers, distillation towers, accumulators, process heaters, catalyst-packed reactors or vessels, condensers, coolers, pumping equipment, auxiliary services (cooling towers, cooling water, electric power, etc.). Operating costs are thus considerable.
In the 1960s and 70s, problems of environmental pollution produced by vehicle combustion were minimal and there were no worldwide regulations issued by governments to control polluting emissions. Because a great deal of publicity had arisen concerning environmental pollution, particularly in cities with high population and vehicular density, in the 80s the governments of highly industrialized nations demanded that refining companies improve the quality of gasolines and diesel fuel and replace petroleum fuels with natural gas in thermoelectric power plants and in industry in general. The principal improvements in fuels (gasoline and diesel fuel) involved production of high-octane, lead-free and low-sulfur gasolines, as well as high-octane, low-sulfur diesel fuel, for the purpose of reducing emission of pollutants to a minimum (unburned hydrocarbons, CO, SO2, NOx, etc.) from internal combustion engines. In the 1980""s, for example, gasoline catalytically produced in Mexico was obtained with a final boiling point (FBP) of 225xc2x0 C. because there were no limitations on sulfur content in these gasolines.
Production of higher-quality gasolines and diesel fuel in these countries was achieved through installation of various types of plantsxe2x80x94hydrodesulftnization, reforming, catalytic, alkylation, TAME, MBE, etc.xe2x80x94some of which make use of by-products from processes already installed in the refineries, to obtain flows of high-octane, low-sulfur hydrocarbons serving as stock for production of high-quality gasoline.
During the 1990""s pollution reached a critical level, and environmental regulations from governments throughout the world became quite strict in all areas (water, ground, air), as pollution is rampant at the world level. The critical global problem of the future is that, as oil fields are exploited, the sulfur content in crude is increasing. The profits from catalytically processed gasoline (high-octane gasoline) are gradually diminishing throughout the world. Due to the sulfur parameters required for public sale of gasoline and established by governments at globally, in order to reduce environmental pollution.
For all the above reasons, the inventor submitting this application investigated various alternatives, among which he considered the most attractive (from technical, economic, and ecological standpoints) to be those consisting of a new treatment for catalytically processed gasolines and intermediate distillates from crude oil, which eliminates the disadvantages of the previous method.
The chemical processing proposed in this invention requires installation of only two vessels (filters) packed with silica gel. The sulfur is absorbed by the silica gel, and the catalytically processed gasoline leaving the filter has low sulfur content. The silica gel-charged filter will operate at the temperature and pressure existing when the gasoline finishes the MEROX treatment, the feature distinguishing the chemical treatment proposed in this invention and existing chemical treatments being that there is a tremendous difference in costs and space for installation of these processes.
Environmental pollution caused by combustion of products derived from o petroleum (diesel fuel, gasoline, etc.) has continued to increase as the number of motor vehicles has risen throughout the world. Because of the specification of sulfur content in gasolines, in the 90s catalytically processed gasoline was obtained with a boiling point of 207xc2x0 C. The maximum sulfur content in catalytically processed gasoline is 0.20%. For a 40,000 barrels/day catalytic plant, the above signifies a production loss of approximately 2000 barrels/day of catalytically processed gasoline. With regard to the processing of crude in its refineries, Mexico currently experiences a production loss of 20,000 barrels/day. The cost per barrel of catalytically processed gasoline is 30.00 dollars per barrel, taking into account the treatment proposed in this patent, this means an additional production of 600,000 dollars a day.
Furthermore, for Mexico this would mean a reduction in loss of foreign exchange, as Mexico now imports this high-octane gasoline from the U.S. and Venezuela.
The principal benefit from the proposed process stems from the fact that, as mentioned above, sulfur content in processed crudes is constantly increasing because the crudes are becoming heavier and higher in sulfer, and the loss in gasoline production continues to increase. This problem is one faced by all crude-refining companies throughout the world.
Considering all the disadvantages of the previous methodology, the inventor submitting this application has conducted a number of studies, tests, and experiments aimed at devising an innovative chemical treatment to reduce sulfur content. The treatment may be used in catalytic production processes for gasoline and intermediate crude-oil product distillation processes in refineries and would be of utmost significance with respect to the engineering involved in the invention.
A principal objective of this invention is providing a chemical treatment based on sulfur-reducing, silica gel-packed filters operating at the exit pressure from catalytic-gasoline and intermediate-crude production processes, to reduce sulfur.